1. Field of the Invention
The present invention relates to windows of the type employing a sash pivoted in a frame about a vertical pivot axis and most commonly used in large multi-story, high rise apartments and commercial buildings. Relatively large windows mounted to pivot about a vertical axis are becoming more common in modern day building structures and especially in multi-story, high rise apartments and commercial buildings. In the recent past, many buildings have been built with fixed windows or glass panes and many problems have been encountered with this type of construction.
Because of power failures, brownouts, blackouts, air conditioning failures and the like, it has become necessary and it is sometimes required in building codes to have windows that are readily opened for emergency ventilation without requiring special tools or keys and without requiring specific technical knowledge of the person opening the window. Weather sealing is a problem with any type of window and it is generally required that the window sashes be tightly gasketed into the frame. When the opening of a tightly sealed window requires a considerable force, after the seal is broken, the window is likely to open very rapidly and this sometimes results in the danger of a person falling out of the window as it is pivoted to the open position. This is especially true with large floor to ceiling windows pivotable about a vertical axis. In order to eliminate this hazard, special keys or wrenches are often required for opening these types of windows and the possession of these keys or wrenches is normally closely controlled by the building management in order to prevent accidents. Normally the keys are not readily available to the tenants or other occupants. In the case of an emergency, such as fire or blackout where rapid ventilation is required, building occupants are often unable to open the windows and the only alternative is to break the glass with the resultant dangers involved in this course of action.
2. Description of the Prior Art
In U.S. Pat. No. 2,812,557, therein is illustrated a window construction in which a relatively large window sash is mounted for pivotal movement about a vertical axis. The Hauck type window as shown, includes a safety system wherein latch bolts must be first released from strike plates and then subsequent opening of the window is limited by sash arresters on the jambs which then must be manually moved out of the path of travel of the sash.
A pair of sash arresters are required and once they are moved away from the path of travel of the sash, the sash is free to swing fully open. Because the sash arresters are mounted on the jambs of the window, very little air ventilation is provided when large windows are involved because of the limited space of the opening in comparison to the overall window size. Because the sash arresters are mounted on the jambs, a standardized system is not useable for windows of various different sizes without extensive modification. The amount of opening that might provide adequate ventilation for a small window with a particular size sash arrester would not be nearly enough for a relatively large wide window because of the fact that the sash arresters are mounted on the fixed jamb of the window frame and the angular amount of opening for a given size sash arrester on a large window would be much smaller than for a relatively small window. Also, the sash arresters are readily operable by the building occupants with the consequent danger that an occupant could fall out of the window upon opening.
U.S. Pat. No. 3,474,572 discloses a key operated window safety fixture for a window sash pivoted on a vertical axis. The safety mechanism is interconnected between the frame and sash at the pivot point of the sash and this is subjected to high operating torque. Accordingly, the safety mechanism must be constructed of extremely strong materials such as costly stainless steels and the like in order to reduce the possibility of failure in a critical situation when relatively large forces are exerted to open the window sash in a panic by personnel or by a high wind load after opening occurs. In addition, extra care is required in order to assume that the mechanism is adequately secured to the sash and frame.